Apparatus for and method of earth bore drilling



J. G. JACKSON Jan. 8, 1957 APPARATUS FOR AND METHOD OF' EARTH BORE DRILLING Filed Sept. 17, 1953 w/lm m 2 s s S n L l I x O Il G //////////T m,

United States Patent C APPARATUS FOR EAND METHOD lifEARIH BORE IDRILLING'Z Joln GordonJackson, Denver, .Colo-., assigner. to .Well

Completions, Incorporated,` Denver, Colo., ,a corpora-v ton'of Colorado Application Septemberi1'7 1953; SerialfNoa 380,789

161Claims'. (Cl.l ZS-LS) mo'r'eparticularly to the drilling `ofsuchv boresby. rotary apparatus and with" .the f use t ot a circulating gas which;A

as usedin" abroad sense,l may be air, acombustiblegas or 'a mixtureofthe tw'oA in the place of' @circulating ilidy orso-called mud In the 'drillingof earth boresb'y rotary. apparatus and' circulating 'gas' there iis danger' of explosions at the surface after the gas has been circulated downth'e'bore an'd'baclc during drilling operations or inthe wellbo're' yduringciro1'1 alreadydrilled. Also, ingas; diilling, thereare problems involved; as; to gas volumes and velocity "Whichhave, not been solved to make this mannerof'drillingfmore eie'tf Oiielof the objects-of my invention is lto produce means associated1 with a'y rotaryy drilling apparatus' which* willi havel less dangerlof gas explosions atthe :surface ywhen gas is f employed as' the i circulatingl iliiid duringdrilli-ng;

A more specific objectlis'toprovide meanslf'or associating with a drilling stem which will cause combustion ofl a oirculatingf combustible gasdurin'gI drillingva'nd in the earthf borey before the gas'v reaches"i thel surface.

Another iobjectf isa `t-ozproduc'e 'byl combustion ofi circulati'ng gas. during drilling aE greater velocity of the gas upwardy to 'the earthvs`1 surface Without increasingI` the.'

volume of: gas being` injected oneven. underf some 1 condi;r tions" employing a less volume of' injectedl gas:`

furtherv object is toi provide for the' dryingl outx of" the" earthsiformations' beingL drilled' when the drilling. is, being accomplished withl circulationof a` gasthus: per.- rnittingV better-'circulation of. the gas Wtihy lesszm'ixtureioi'. Water withl drillingcuttings; andxfurther. an. increase in: a, permanent mannerpthe permeability of formations bythe actions of. theA heat resulting from the combustione Other objects ofthe.' invention will become; apparent: from thev following description taisentl in connection with` the accompanying drawings in which:

Figure li is across; sectionalE view ofthey lower,y endof a rotary drilling structure' having; associated with the hollow drilling stem above the bit apparatus for eau-sing combustionfof the. circulating. gas. and thereby carrying out my improved'drilling method;

Figure 2. is cross sectional View through the retriev-v where itpasses tlirouglik the. usual ,floatvalvevF towthe; `.drill blt- Dfand then upthe outsider-ol Athe drillstemhtl. to` the. eartlifs surface .with considerable. velocity@ During itscirculatiomit.picks.up,the.. cuttings:V from the. drill b it. andgcarriesV them out,v said cuttings beingrelativelv small, and. due tothefgas velocity, theywillbe( pieke-Clupy and` carriedalong. with thel gas;VIK AnyA tendencyrof; aibazclcl pressure. will'be preventedv by.vv the, oatgvalvef F. Said;A valve. also prevents ,undesirable .conditionsfrorn develQPrf ing, aswill become apparent.y

The .use ot gas as,a. l circula ting mediumnswell known,y either.; as. air orlamaturalgas. or; a mixture; thereof. Re; gardless otI whith1 is., used; thereexists the darniger1 of, explosions at the earths surface whenthefoxygenvand. hydrocarbon content, or,v other. explosive ,mixture is,- condulctiveaforl suchandpthere is the,.necessaryi igniti'ngxfactor present. It .is-.thisgdanger-that by. reason .of` mvinveiltian l .intend .to eliminate. and, at.th e saine.. time. obtain. mani/. other beneficial resu-,ltsfrom.theusefof gasasa cir l fluid in the. drilling, of earth .boresby a ,rotary drilling i bit;

able ypower unity for accomplishing the igniting7 of the? In accordanewith mvinvenrion, I nravide meanslter. igniting, the..` circulating.; combustible gas. after it has n. circulatedfpastthe drillingbit.4 Ifainisusedasthe circ at ingflluid,`v itin itselfgwill not.becoinbustible, but during its., circulating. it. may, be. mixed witlifnatural combustible gases comingfromthe; formations.,beingidrilled. In, sach event.. thqmixture. Willbedgnited in the bore.; and| all danger of undesirable explosionswill bey eliminzlxtteiitY IE combustible. gas or. a. mixture, thereof with air. is,y thec circulating. 'uigc'hthenf combustion will always occur with niyinvention iii-,the boreandmoidanger otexplosions at the. surfacewilbbe present. andin addition thefothery agi; vantagesy occurring.. from theburningxof. the gas in the, bore will be present,4 which isf anl importanty featriiireolE rnv-inventiva An example Iof uthe apparatus I- can employ in, carrying out my inventionfinludingmy. improvedmethod ofi earth. boredrilling by gas is shown in the drawings. In. the drill stern aboveI thedrillingbit l. insert a4 special,subU.| The distance.y of thus sub above the bit may-vary iny aecordance with conditions.. It. may be` l0 feet, 2OV fee/lt, 3().f eetL or even. more.y This subU is hollowy toper'rnity circulationnot the. gasfand suitablyA threaded. at itsupper andlower ends tqtgintothestemlas any/,section thereof.

Carried'by the sub. are.. a pluralityl of igniters ors plugsl, preferably, in a circular arrangement at one section. of the. sub. Each of these plugs, as best sliown in Figure; 3, ia soconstructedas to be. screwed into the wall of the sub and has abody. 10., an insulating part 1l therein and ai spark. gap. 1,2y by, spaced conductors t3, and t4 carried respectively; byA the. insulating. part and thebody. The spark plugs are caused to. be tired` by a power unit P whichr isot the removable type. This unit has an outer case 15, .theI lower end of which is closedby a plug.

carrying` a conductor 17 embedded iny insulating7 material 18? which can be of heat resistant rubber or otherhet resistant insulating material. The conductors lead from a contact button 19 inside the case to a conductor ring 2.0. carried by the insulation 1S outside the. plug 16. BDWed springs 21 are attached to the conductor ring so asto provide. a conductor to the *spark plugs l, of which will have their conductor posts 113 arranged rto be Connected tqsether by a fins l2.2 @arr-ieri by any .Suitable insulating means with which the Sprinsswn engage resardless. cf the :stative positief; et the mwst unif- The power unit has; a nose. nisse N Whsh @sensatie 'lassiing plate 23 carried at the bottom of sub U as shown in Figure 1.

- Within the casing is a replacement unit R which will include batteries 24, an induction coil 25 and a vibrator 26 to produce an intermittent surge of increased current to tite the spark plugs.I Figure 3 shows a wiring circuit including these elements and a usual condenser 27 which are intended to illustrate only a simple and well known circuit arrangement whereby the plugs can be red. The unit R is held in the case by a closure plug 18 and between it and the unit is a coiled spring 29 acting as a eonductor from the unitR to bowed leaf spring 30 caried on the' outside of the ca se which will contact the upper end of sub U and complete the circuit to the shells of the 4spari; plugs and the conductors' 14 carried thereby. The plug 28 can have a pickup spear 31 whereby the lcomplete power unit P can be removed from its position in the sub U when desired by a' retrieving line with an overshot attached to its lower end to connect Onto the spear, as is known procedure. The lower end of the removable unit has a contact lbutton 32 whereby the lower end of the unit will be placed in circuit with lthe spark plugs, said button 32 engaging button 19 when the unit is in place in the case 15.

From the foregoing description of apparatus embodying my invention and usa-ble for carrying out my im proved method of drilling, it will ybe seen that all danger of exploding mixtures is eliminated from any circulating gas which may contain such a mixture either as it is circulated from the earths surface or as it may occur during circulation. I have shown one direction of circulation involved, butmy invention also contemplates a reverse type of circulation whereby the circulating gas (air or a combustible mixture or a straight hydrocarbon natural gas) moves down the bore outside the drill stem to the bit and then up the bore inside Ithe stem. ln such case the firing of any combustible gas mixture will occur after the circulating gas 4has passed the drilling bit and the igniters will be shifted in a proper manner to take care of the change in direction of the circulating gas.

In Figure 4 there is illustrated one suitable manner of so shifting an igniter and referring to this figure, spark gap 12 is formed by conductors 13 and 14', the former being part of a member 33 engageable with spring 21 and the latter Ibeing a part of a ring 34 conductively connected with sub U. The ring 34 and member 33 are properly insulated by insulating means shown at 35 and 36.

When the gas mixture is tired, many beneficial results are obtained besides eliminating the danger of explosions at the surface. By tiring the gas, heat is created and this will increase lthe Volume of the circulating gas and consequently less pressure will be required Vas the greater volume increases the velocity and therefore less volume of gas needs to be supplied at the surface to obtain a predetermined upward rate of flow. The heated tired gas also tends to dry out moisture from the earths formations and also permanently increases the permeability of the formations, due to increased .heat involved.

I am aware that modifications in structure of the apparatus disclosed as embodying my invention is readily possible, and also that the specific steps described in the method cany be varied without changing the fundamental principles involved. Therefore, I desire it to be understood that the scope of my invention is not -to be limited except in accordance with the terms of the appended claims and equivalents thereof.

What is claimed is:

l. In earth bore drilling apparatus, a hollow drill stem, a drill bit at the lower end thereof, means for circulating a gas under pressure from and to the earths surface past the drill bit to pick up cuttings and for other purposes, said path of circulation from and to the earths surface including in one direction the interior of the stem and in the opposite direction the exterior of the stem, said `gas being combustible or capable of becoming combustible by a mixing with combustible gas coming from the earths strata exposed to the bore being drilled, and means carried by the drill stem at a point above the drill bit for causing circulating gas which has passed the drill `bit and is on its return path to the surface to be fired in the bore. p

2. The earth bore drilling apparatus of claim l in which the means for tiring comprises an igniter carried in a special sub interposed in the drill stem.

3. The earth bore drilling apparatus of claim l together with means for preventing any reverse circulation of the circulating gas by way of its downward path as a result of explosions during tiring.

4. In earth bore drilling apparatus, a hollow drill stem, a drill bit at the lower end thereof, means for circulating a gas under pressure from the earths surface down through the hollow drill stem past the drill bit and back to the surface exterior of the drill stem, said circulated gas being combustible orcapable of becoming combustible by a mixing with a combustible gas from lthe formations being drilled after the circulated gas reaches the drill bit, and means carried by the drill stem above the drill bit for burning combustible gas in the bore after the circulating gas has passed the drill bit and comprising an igniter in the path of movement of the gas along the exterior of the stem.

5. The drilling apparatus of claim 4 together with valve means positioned in the stem above the bit for preventing return ow of circulating gas up the drill stem.

6. The drilling apparatus of claim 4 in which the igniter is carried in a wall of a hollow sub in the drill stem.

7. The drilling apparatus of claim 4 in which the last named means also comprises an electrical power unit for tiring the operating igniter intermittently.

8. The drilling apparatus of claim 4 in which the last named means also comprises an electrical power unit provided with means cooperating with the iguiter to cause it to operate and means for detachably mounting the unit on the stem for ready insertion in or removal from the drill stem without pulling the stem from the bore being drilled.

9. In earth bore drilling, a hollowdrill stem, a drill bit at the lower end thereof, means for circulating a gas under pressure from the earths surface down through the hollow drill stem past the drill bit and back to the surface exterior of the drill stem, said circulated gas being combustible or capable of becoming combustible by a mixing with a combustible gas from the formations being drilled after the circulated gas reaches the drill bit, means carried by the drill stem above the drill bit for burning in the bore combustible gas during its return path to the surface and after the circulating gas has passed the drill bit and comprising igniters in the path of movement of` the Agas along the exterior of the stem, and electrical power means for operating the igniter, and means in the drill stern for preventing return circulation of gas up the drill stem during combusition of gas mixtures.

l0. A method of drilling an earth bore by a hollow drill stem with a rotatable bit on its lower end, said method comprising the circulating ofr a gas from the surface to the drill bit and return to the surface to thereby carry out earth cuttings and for other desired purposes, said circulation in one direction being by way of thc interior of the hollow stem and the opposite direction by way of the exterior of the stem, and during the circulation of the gas below the surface tiring in the bore any combustible mixture thereof and at a point in the circulating path which is after the gas has passed the drill bit and during its return to the surface.

1l. The method of claim 10 in which the circulating of the gas is down the interior of the drill stem and then up the bore exterior of the drill stem and the firing takes place at the exterior of the stem and at a point relatively close to the drill bit but below the earths surface.

12. The method of claim 11 in which the tiring is accomplished in an intermittent manner.

13. The earth bore drilling apparatus of claim 1 wherein the means carried by the drill stem includes an igniter, and means for operating the igniter for intermittent ring.

14. The earth bore drilling apparatus of claim 1 wherein the means carried by the drill includes an igniter, an electrical power unit for tiring the igniter, and means for detachably mounting the unit on rthe stem so that the unit may be inserted and removed from the well bore and stem without pulling the stem.

15. The earth bore drilling apparatus of claim 2 wherein there is provided an electrical power unit for tiring the igniter, and means for detachably mounting the unit in the sub so that the unit may be inserted and removed therefrom while the drill stem is in the bore.

16. Apparatus as defined in claim 15 wherein the last named means includes bowed leaf springs on the exterior of the unit engageable with the interior surface of the sub, said springs being electrically conductivek for placing the igniter in circuit with the power of the unit.

References Cited in the tile of this patent UNITED STATES PATENTS v1,529,409 Condra Mar. 10, 1925 2,337,269 Piety Dec. 21, 1943 2,548,463 Blood Apr. 10, 1951 

